The present invention relates generally to controls for systems of surface mount machines and their auxiliary equipment, and more particularly, to a system and method for a control system interface between feeder exchange systems or feeders and surface mount machines.
Surface Mount Technology (“SMT”) is used to assemble printed circuit boards (“PCB's”) by mounting components on a surface of the boards. Commercial pick-and-place machines are commonly used to automate SMT processes, often under computer control, and to assure that components are placed at their proper positions on PCB's.
A feeder is used to supply a surface mountable component to a pick-up head of a pick-and-place machine, which then places the component on a PCB. Feeder devices may be microprocessor controlled and may use mechanical or pneumatic conveyors, pneumatic cylinders, pneumatic valves or electrical motors, among other devices, to move components from the feeder device to the pick-up head.
Many types of feeder are available and may be used, depending on, among other things, the specifications of the pick-and-place machine and the components being handled. Tape, stick, bulk, and tray feeders are common types. In tape feeders, for example, components are packed on a tape and released to the pick-up head as the tape passes through the feeder. Stick feeders release components from sticks or tubes, often by vibrating the stick or tube or by releasing compressed air to slide a component from the stick or tube and send it in a desired direction.
Feeder auxiliaries and components to be mounted on PCB's may be placed on carts or trolleys. A feeder exchange system (“FES”), for example, often includes a feeder exchange cart, trolley, and other devices designed to provide seamless integration of feeders to surface mount machines, by, among other functions, automatically replenishing the supply of components to the feeder. If components for the next production run are kept on hand and rapidly connected to a pick-and-place machine at the end of a production run, the time between production runs may be reduced to a matter of minutes.
Many commercially available feeders, FES's and other auxiliaries are adaptable to the many different models of pick-and-place machines, being able, for example, with respect to feeders, to accommodate differences in clearances, pick point location and mounting design, in particular, differences between the more common models of pick-and-place equipment from manufacturers such as Fuji, Panasonic, Sanyo, Siemens, Universal, Zevatech, TDK, Philips, Quad, Intelliplace, Samsung, Mamiya and Tenryu.
Currently, however, control and operating data is transferred between surface mount machines and their auxiliary equipment via hard electrical contacts or through another, physical connection.
In WO0103489 A1 an optical waveguide and optical transmitter and receiver serve as a communication link between a control unit of a pick-and-place machine and a control unit of a feeder unit, thereby avoiding a cable connection that must otherwise transmit information in a fixed grid pattern or raster. The feeder may be coupled to any position on the optical waveguide, which serves as a bi-directional bus.
Non-physical contact (e.g., optical) data communications systems are well known in communications and data processing. For example, U.S. Pat. No. 3,705,986 to Sanders et al. discloses a point-to-point digital data transmission system employing pulse modulated infrared or light beams in which a pair of optical transceiver units link one computer installation to another via line of sight communications.
U.S. Pat. No. 6,353,693 to Kane et al. discloses an optical connection used within a pick-and-place machine. A pair of optical couplers are interposed between a stator and a rotor in a slip ring unit of an electronic component-mounting apparatus for permitting bi-directional communication between a stator-side circuit and a rotor-side circuit.
A non-physical contact interface may also be accomplished using RF signals. Radio frequency identification tags are in use by, for example, Yamaha IM Company to transmit the serial number of a feeder auxiliary to a control system of a pick-and-place machine by close proximity RF transmission.
Transmit/receive modules using non-physical contact coupling such as RF or optical coupling, for example, Agilent Technologies' HSDL-3200 infrared transceiver module, which has a small size and a link distance of 20-30 cm, are commercially available and readily adapted to use in SMT.
A principal disadvantage associated with conventional feeders and other pick-and-place machine auxiliary devices, is that the controllers for these feeder mechanisms must for an acceptable level of functionality each be mechanically connected, by a waveguide or by an instrument cable. A cable may carry as many as sixty signal lines, to a surface mount machine or a feeder. A cable, in particular, must match the particular feeder device with the particular placement machine. The physical layout of hard electrical contacts is unique between, for example, different types of feeders/feeder carts and pick-and-place machines.
It is, therefore, highly desirable to have an efficient and effective means of automatically interfacing feeder mechanisms to various pick-and-place machines, thereby eliminating the need to connect, disconnect, and reconnect instrumentation cables during operation of surface mount machines and their ancillary equipment.